The sum runs over all distinct four-point one-loop graphs with
trivalent vertices. We denote the gauge-theory coupling constant by \(g\) . We label each graph by an integer \(i\) . The \(S_i\) 
are the symmetry factors of the graphs. The color factor \(c_i\)  of
each graph is obtained by dressing each vertex by a structure constant
\(\tilde{f}^{abc}\) , since we take all particles to be in the adjoint
representation. Our normalization of the structure constants follows
that of Ref. [1]}. The denominator \(D_i\)  contains the propagators of
each graph. Finally, we capture all non-trivial kinematic dependence
by the numerator \(n_i\) .
